The proposed longitudinal study of psychopathology compares the development, the comorbidities and the risk factors of disruptive disorders and antisocial behaviors (ASB) in Puerto Rican children and adolescents in Puerto Rico (P.R.) and the mainland U.S. Previous studies have shown that rates of ASB among children and adolescents are lower in P.R. than on the mainland U.S., even when rates in P.R. are compared to rates among mainland Hispanics. Existing developmental studies of ASB have never included any Hispanic group in sufficient numbers to assess features in the development of ASB that may be characteristic in these minorities. The study uses cohort sequential design to describe the development of ASB in Puerto Rican youth in the South Bronx in New York City and the San Juan Metropolitan Area in Puerto Rico. Probability samples of boys and girls aged 5 through 13 years will be obtained (N=1,575) at each site (Total N=3,150) and followed over three waves to examine whether differences in rates among Puerto Rican children at these two sites are explained by differences in the age of onset, in the severity and persistence, and in the associated risk factors of ASB. The study will assess the comorbidities of ASB and conduct problems in this population cross-sectionally and whether the sequencing over time between ASB and its comorbid conditions differs between island and mainland Puerto Rico children. Particular emphasis will be placed on the comorbidity with substance use and abuse and on the role of Attention Deficit Hyperactivity Disorder (ADHD) in increasing the risk for the development of ASB and its persistence. The study will also evaluate the association between individual, family, peer, and community factors and the development of ASB in each setting. Among the risk and protective factors to be examined are possible cultural determinants, such as strong familial attachments (familism), parental and neighborhood monitoring, and type and level of acculturation. The study is unique in several ways. It assesses the development of antisocial behaviors in both boys and girls as a function of the characteristics of different settings (the island vs. The mainland). It applies the same design to study members of a single Hispanic minority in their native environment as well as in the country to which they have migrated, providing a quasi-natural experiment that will permit an assessment of the influence of settings, culturals factors and cultural change on the development of ASB and delinquency in this minority. This will be the first extend longitudinal study on youth anti-social behavior in any major Hispanic group. It will add information to growing fund of empirical data about the patterns in the development of antisocial behaviors that have been assessed in other ethnic groups, the generalizability of those findings and what may be unique features characteristic of ASB in this minority. The data can also inform preventive efforts and the shaping of culturally sensitive treatment interventions in this and other Hispanic groups.